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Detecting field presence in dbf
Message
From
27/07/2007 17:21:06
Cetin Basoz
Engineerica Inc.
Izmir, Turkey
 
 
To
27/07/2007 13:34:27
Mike Yearwood
Toronto, Ontario, Canada
General information
Forum:
Visual FoxPro
Category:
Coding, syntax & commands
Environment versions
Visual FoxPro:
VFP 9 SP1
Database:
Visual FoxPro
Miscellaneous
Thread ID:
01244177
Message ID:
01244275
Views:
22
>Hey all
>
>Some time ago I think Fabio Lunardon demonstrated using fsize to check for the presence of a field. What thread was that? I can't find it though I looked.
>
>Considering the need to manage SET COMPATIBLE for a UDF to use FSIZE I can't see it being the fastest way.
>
>I have used a UDF based on TYPE() and it is faster than a UDF using FSIZE that also handles setting and resetting SET COMPATIBLE. I think I found FIELD() is faster.
>
>There is another consideration. Using a UDF can be slow, so using an idea that is in my FoxPro Advisor article: http://advisor.com/doc/17440, the command that can detect a field with the fewest external dependencies could be directly injected into code. It seems the easiest and fastest is to use FIELD().
>
>Did FIELD() always accept the fieldname and alias?

Probably best one is:
field(upper(m.Field)) == upper(m.Field)

fsize() is better than Type() thinking reliability. Afields() + ascan() is yet one of the best IMHO.
Cetin
Çetin Basöz

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